"It's one of those things that you better get on top of," Matheny said. "It was good that we got that information early so we could shut him down so he couldn't continue to throw and possibly make it worse."
Losing Harris is a subtle but meaningful blow to the bullpen, especially considering his recent output. He allowed one hit in his last five appearances (six innings).
Matheny said that Scruggs was optioned not because of something he did or didn't do, but because "we just needed arms."
Scruggs was called up for a second time this season on June 19, and made 10 starts (16 appearances) in that span. He hit .268 with seven RBIs, but in 18 at-bats in July, he posted a .158 on-base percentage.
With Harris' absence and increased work from the bullpen recently -- Carlos Villanueva and Miguel Socolovich each threw two innings on Friday -- the additions of Tuivailala and Greenwood are much welcomed by Matheny.
Tuivailala was Memphis' closer, earning a 3-0 record in 30 appearances with a 1.78 ERA and 12 saves in as many opportunities. He made three showings for St. Louis in May, allowing two earned runs and two hits in four innings.
Matheny said that Tuivailala's experience as a closer is beneficial, and that he could even serve in that role for St. Louis if anything happens to regular closer Trevor Rosenthal.
"Just pitching in those high-leverage situations is great. It's a great test for him, great work for him, great preparation for coming up here," Matheny said.
Meanwhile, Matheny believes that Greenwood can eat some innings from the bullpen when necessary. Since becoming a regular starter with Memphis, Greenwood has posted a 5-2 record and 3.88 ERA in 51 innings.
Greenwood is 2-1 with a 2.01 ERA in his last three starts, and he appeared in 19 games (one start) for St. Louis last season, going 2-1 with a 4.75 ERA.
John McGonigal is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.